Ultrasound shows fetuses’ interest piqued by face-like lights

Using fetal ultrasound to observe prenatal perception and attention, U.K. researchers have found that third-trimester humans respond to patterns of light mimicking a face.

The study was small and preliminary, and overall response to any light pattern was relatively low. Still, the fetuses turned their heads to visually follow the face-like light patterns at about four times the rate they did so with other patterns.

“Vision really was the last of the sensory systems for us to understand,” lead author Vincent Reid of Lancaster University tells NPR. “And that’s because, until now, we haven’t able to look at vision.”

The study was published online June 8 in Current Biology, which has posted it in full for free.

Click the link below for NPR’s coverage.